This invention relates to an improvement in liquid crystal cells which display a predetermined pattern.
The conventional liquid crystal cell generally comprises a pair of transparent supports typically of a transparent glass sheet, each inner surface of the transparent suppoorts carrying a transparent conductive coating of a desired display pattern and an overlying transparent insulating coating for controlling molecular alignment in a layer of liquid crystal composition. The two transparent supports are held such that the inner surfaces of the two transparent supports are opposed in parallelism via spacers to define a cavity in which the liquid crystal composition is injected.
However, under non-electric field condition or when no voltage is applied between electrodes on the two transparent conductive coatings in the conventional liquid crystal cell, the shadow of the display pattern stands out in strong relief. Another disadvantage is that the display pattern is somewhat unclear and contrast is poor when a given voltage is applied between the two transparent conductive coatings to display the desired pattern. As a consequence of the inventors' effort to find the cause of the above discussed disadvantages, the inventors revealed that there is an appreciable difference in refractive index between the transparent conductive coating forming the display pattern and the transparent insulating coating in contact with the transparent conductive coating and extraordinal reflected light appears at the boundary between the transparent coductive coating and the transparent insulating coating.